The present invention relates to a gas turbine engine combustor having at least one trapped vortex cavity and, more particularly, to a combustor having cavity with dual counter-rotating vortices.
Advanced aircraft gas turbine engine technology requirements are driving the combustors therein to be shorter in length, have higher performance levels over wider operating ranges, and produce lower exhaust pollutant emission levels. One example of a combustor designed to achieve these objectives is disclosed in U.S. Pat. No. 5,619,855 to Burrus. The Burrus combustor is designed to operate efficiently at inlet air flows having a high subsonic Mach Number. This stems in part from a dome inlet module which allows air to flow freely from an upstream compressor to the combustion chamber with fuel being injected into the flow passage. The combustor also has inner and outer liners attached to the dome inlet module, which include upstream cavity portions for creating a trapped vortex of fuel and air therein, as well as downstream portions extending to the turbine nozzle. U.S. Pat. Nos. 5,791,148 and 5,857,339 also disclose the use of trapped vortex cavities in combustor liners. Fuel is injected into the trapped vortex cavities through a portion of the liner forming an aft wall of such cavity. Fuel is also injected into the flow passages of the dome inlet module via atomizers. It is desirable to have a combustion chamber, such as the one in Burrus, with better flame stabilization and flame propagation and which improves the combustor's performance characteristics of combustors, efficiency, NOx and CO emissions, and altitude-relight.